B chromosome diversification pattens in Astatotilapia latifasciata: A comparative analysis between B chromosome and A complement

• Grant number: 11/23967-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2012
• End date: December 31, 2012
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Diogo Cavalcanti Cabral de Mello
• Grantee: Rafael Takahiro Nakajima
• Host Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

The B chromosomes occur in about 15% of eukaryotes species, being primarily composed of repeated DNAs and heterochromatic. Some studies have been performed regarding the analysis of distribution, frequency, inheritance mechanisms, structure, and origin of these chromosomes. On the other hand, deeper analysis related to the diversification patterns of DNA sequences present in the B chromosome and shared with the A complement have not been extensively performed. The cichlid fish have been received great scientific interest due some species have passed through an extensive adaptive radiation process. In some species of this group, the presence of a B chromosome was described, as observed in Astatotilapia latifasciata (previous refered as Haplochromis obliquidens). The present project aims to analyze the genomic content, origin and evolution of the B chromosomes, using as model A. latifasciata. In this species, besides the classic chromosomal analysis, molecular studies related to sequences present in the B chromosmes (shared with the A complemente) will be possible through the use of molecular data and tools, such as microdissection, nucleotide sequencing, and genomic analysis using bioinformatics. These analyses integrating the physical mapping and molecular data are promising in the elucidation of a myriad of questions related to B chromosome diversification mechanisms, enabling a deeper knowledge concerning the possible biological roles of these elements in eukaryotes. (AU).